1. Field of Invention
This invention relates to an emergency security system and, more particularly, to an improved acoustic alarm system suitable for use by the general public.
2. Description of the Prior Art
In many emergency situations, such as in cases of violence, it is desirable to discreetly summon immediate aid. Such conditions may arise in large office buildings, in educational institutions, in subway stations, in penal institutions, in hospitals, or in any other area susceptible to violence, the threat of violence or where it is otherwise particularly desirable to remotely trigger an emergency alarm.
Remotely triggered emergency alarm systems have been provided for schools, hospitals, penal institutions and the like. U.S. Pat. No. 3,750,131 discloses a suitable remotely actuated emergency alarm system using acoustic energy for the use and protection of selected institutional personnel. The system has acoustic detectors at various locations and these detectors are coupled to a central control station from which aid may be sent to the indicated locations. Members of institutional staffs may be equipped with a small concealable ultrasonic transmitter which, when hand-actuated by the individual staff member, discreetly signals the occurrence of an emergency to the nearest hidden acoustic detector and thereby relays an alarm to the central control station.
However, the particular concealable transmitter disclosed in the above patent is suitable only for use by trained, responsible personnel. The transmitter is too readily triggered by the untrained user; thus, it can be accidentally triggered too easily. This shortcoming could produce frequent false alarms. Furthermore, use of the transmitter disclosed by the above patent is subject to abuse by the general public because the transmitter can be readily re-cocked and re-triggered. Such a transmitting device might too readily be used to intentionally create false alarms within the system, thus reducing its effectiveness and causing confusion.